It was Anna Wintour, the redoubtable Editor of American Vogue, who a couple of summers ago almost single-handedly made the cardigan chic. She would saunter out in a Prada or Chanel number teamed with a lightweight cashmere cardie, looking a million dollars. She showed us that, no matter how grim the skies, you could still don your summer wardrobe provided you had one of these useful little accessories to hand. They are softer than a jacket, much lighter to carry and look as good with tea dresses as they do with suits or jeans.

It's a ploy that I adopted all through the grim August days and, thanks to a cache of cardigans garnered over the years, I'm still in summer mode. Of course, everybody has always known that the cardie was the most practical and useful of garments, but they used to come in such solemn, remorselessly classic form that they seemed unrelated to Planet Fashion. These days almost every designer has had a go at making them infinitely more desirable. They come inexpensively at the bottom end of the market - Uniqlo, Primark and Marks & Spencer - and they come from designers as varied as Sonia Rykiel, Vivienne Westwood, Luella Bartley (www.netaporter.com is selling a particularly nice bright blue one for £180) and Donna Karan.

But let me draw your attention to a few ranges of which you may not yet have heard. First, there's Tania, who some ten years ago was one of the first to do cashmere dresses. She uses fine-quality cashmere, finished in Italy, and turns out a sweetly feminine collection of dresses trimmed with lace, as well as delicious cardigans with jewelled buttons and delicate trimmings. Because of the handwork, the Tania range is expensive (cardigans start at £380) but, bearing in mind these economic times, she has just launched Tania Too, with cardigans starting at half the price. The cashmere is of the same quality, but there are fewer trimmings. Change the buttons yourself, add a few trimmings at home and you have just as exclusive a piece for a fraction of the price. The best place to see the cardigans is at The Cross (020-7727 6760), where the Notting Hill yummy mummies can't get enough of them. From October some of the Tania range will be sold online (www.savoir-faire.com); in the meantime, call 020-7602 3168 for stockists around the country.

I came upon Queene and Belle recently at Jane Davidson's shop at 52 Thistle Street in Edinburgh (where the fashionable set seem to shop when they're not in Harvey Nichols). Doreen Keen and Angela Bell were designers at Pringle, but apparently became bored with doing yet another plain grey cardigan and so have brought out their own wonderful couture line. These are not cheap, but every single piece is special and to be treasured for years. Madonna and Michelle Pfeiffer are among their many fans (www.queeneandbelle.com; call 01750 23419 for stockists). They add couture touches in the shape of knitted motifs or embroidery and they like to have fun. Sometimes the cardigans are plain on the front, but turn around and there's a whacking great image of a Native American headdress or enormous stars on the back. Prices start at £350 for cardigans.

If you want one fantastic comforting garment to see you through the winter, you should look at Donna Karan's cashmere Cozy. You can wear it with the sides hanging loose, more or less like a jacket; you can tie it, wrap it, knot it and create about 12 different looks. Wear it with jeans, over camisoles, over dresses. It is £145 from Selfridges, in all sorts of colours (if you buy it in magenta, £85 of that goes to Selfridges' Breast Cancer Care campaign).

Finally, if your cashmere has been attacked by moths, let me draw your attention to the bright idea of Jeanetta Rowan-Hamilton, a designer who refashions vintage cashmere that she picks up in car boot sales or from thrift shops. By appliquéing hearts or beads over stained or old patches, and adding ribbons and trims, she transforms them. Check them out on www.nettlescashmere.com (or call 020-7584 3030). You could copy her idea on your own dilapidated cashmeres, or - if you're lucky - you could persuade her to do it for you.

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